1. Technical Field
The field of art to which this invention pertains may be generally located in the class of devices relating to tools for installing threaded elements. Class 81, entitled Tools, United States Patent Office Classification, and in particular Subclass 53.2, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Background Information
It is known in the construction art to employ threaded steel studs or anchors in holes formed in concrete, masonry, rock or the like, and to secure the studs or anchors in place by a chemical adhesive material. Heretofore, one method employed for inserting a threaded steel stud or anchor into a hole in concrete was to drop a breakable capsule filled with a chemical adhesive into the hole and then pound the stud or anchor into the hole. A disadvantage of the method of pounding a stud or anchor into a hole is that the capsule material is merely compacted into the hole and the chemical adhesive stayed mostly in the bottom of the hole in the concrete or the like. Another method of installing a chemical adhesive stud or anchor in a hole in concrete or the like, is shown in U.S. Pat. No. 4,404,875. The installer drive unit shown in the last mentioned patent includes a cylindrical shank which has a central portion having a hexagonal cross section and an upper end adapted to be inserted in a conventional chuck of a rotary drill. The lower end of the drive unit shank is provided with threads of the same pitch as a threaded stud or anchor which is to be inserted into a hole in concrete or the like. The drive unit is provided with a connector nut that is used to attach it to the threaded outer end of a stud or anchor. The distal end of the threaded portion of the drive unit is generally convex, so as to reduce friction with the flat end of the stud when the two are joined together by the connector nut. In order to release the nut from the stud after it is driven into a hole in concrete or the like, two wrenches are required. One wrench is required to hold the hexagonal portion of the drive unit and the other wrench is used to release the connector nut. A disadvantage of the last described structure of the installer unit of U.S. Pat. No. 4,404,875 is the fact that much time is lost on the job in having to manually release the drive unit with a pair of wrenches. The wrenches also comprise extra tools which must be employed in the use of the last mentioned drive unit.
U.S. Pat. Nos. 2,336,157, 2,933,960, 3,280,666, and 4,513,643 illustrate further examples of prior art tools for installing threaded studs and similar elements.